Global Patent Index - EP 0789937 B1

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EP 0789937 B1 20000517 - PIEZOELECTRIC MOTOR

Title (en)

Title (de)

Title (fr)

Publication

Application

Priority

DE 4438876 A 19941031

DE 19522072 A 19950617

EP 9504148 W 19951023

Abstract (en)

[origin: WO9613868A1] A piezoelectric motor achieves maximum mechanical performance, high safety of operation and low costs with a negligible exciting voltage. The piezoelectric engine has a stator whose oscillator designed as a closed waveguide is provided with at least one generator of an elastic travelling wave for the waveguide. A rotor is frictionally engaged by a functional surface of the oscillator. The elastic travelling wave generator is as long as the generated wavelength and consists of a base generator and two supplementary generators that generate elastic longitudinal stationary waves having the same amplitude and wavelength. The stationary waves are offset with respect to the wave generated by the base generator by +/- 1/3 of the wavelength along the waveguide. Exciting sources are associated with the base generator and the supplementary generators. The supplementary generators and their exciting sources are designed in such a way that the stationary waves they generate are phase shifted by +/- 2/3 pi with respect to the stationary wave generated by the base generator. The length of the waveguide is the same as the wavelength of the stationary wave or is an integral multiple thereof.